The well known energy saving value of compact fluorescent light bulbs often offsets their high initial price. Usage of compact fluorescent light bulbs is most attractive when their installation requires little or no lighting fixture retrofitting costs. While the frequency of their use has been increasing in many different lighting applications, the compact fluorescent light bulb's shape in combination with the size of ballasts continues to inhibit their usage in common table lamp fixtures.
Compact fluorescent light bulbs are long by necessity, and the ballasts are large and bulky due to their electrical and magnetic requirements. Traditionally, the ballast is positioned directly below the light bulb, making the combination of the two units too tall to fit into a standard table lamp configuration. Therefore, in order to install the light bulb and ballast combination in an average table lamp so that they will fit into the fixture, the standard-size harp typically used in a table lamp must be replaced with an extended harp. However, because most lamp shades are proportioned to fit over a standard-size harp, they are too short for an extended harp. Accordingly, when replacing the harp, the lamp shade must also be replaced. Therefore, the cost of using a compact fluorescent light bulb in a common table lamp becomes prohibitive.